The invention relates to abrasive members comprising an electrically conductive or non-conductive open, porous layer supporting a metal structure which carries an abrasive material. In a method for making such an abrasive member, the metal structure is formed by electroplating or electrodeposition on the porous layer in the presence of abrasive material, such that the metal structure penetrates at least partially through the holes or pores of the porous layer.
Abrasive members of this type are typically used for the purpose of removing stock and in the fine grinding or smoothing of hard materials such as glass, hard plastics, metal and other hard materials such as stone. Dependent on a particular operation and/or the shape and curvature of an object to be treated, the abrasive member may take the form of a flexible, semiflexible or rigid body such as a disc, sheet, handpad, block, tape or endless belt etc.
The metal structure and abrasive material are usually applied to the porous layer by an electroplating or electro-deposition process. Electroplating or electro-deposition of a metallic coating on an electrode is a technology well-known in the art, such as for example described in GB-A-8,447 (Elkington et al. 1840). Electroplating is essentially a surface treatment. The material to be treated is made the cathode in an electroplating metal containing electrolyte solution or bath. By connecting a DC power source with its positive pole to an anode in the bath and its negative pole to the cathode, the metal is reduced from the bath and deposited onto the cathode.
GB-A-1,375,571 (Prowse) discloses a method of making an abrasive member of the type mentioned above, wherein the porous layer supporting the metal structure is a metallic or non-metallic flexible, semiflexible or rigid layer of mesh material or a sheet metal object, having a solid or perforated surface.
GB-B-2,223,966 (Diaforce Ltd.) relates to the making of an abrasive member wherein the porous layer is an electrically conductive flexible mesh material.
EP-B-0,013,486 (Interface Developments Ltd.) discloses a method of making a flexible abrasive member by electrodeposition of an abrasive metal structure onto a porous layer of electrically non-conductive mesh material such as woven fibre cloth or fabric.
Woven fabrics are made by interlacing and looping or knotting together yarns or fibres in a highly regular repetitive design in any of many well-known ways to form a mesh pattern or gauze. The strength of the fabric is derived from friction between the fibres.
Abrasive members of this type have to be used under any circumstance with a coolant such as water or soluble oils, because otherwise the flexible abrasive member will be destroyed in a very short period of time due to the heat developed. It is of utmost importance not to use a coolant which would affect the abrasive member or the object to be treated. Further, it is vital that grinding fluids be kept clean. A dirty coolant will recirculate metal and abrasive chips, thus affecting the finish desired. Accordingly, grinding machines are required which have facilities for wet-grinding, such as a coolant supply tank, recirculating mechanisms, cleaning or filtering means and a settling tank for sludge. In order to promote the efficiency of the filtering and recirculation the sludge has to be removed frequently.